001 /**
002 * JDBM LICENSE v1.00
003 *
004 * Redistribution and use of this software and associated documentation
005 * ("Software"), with or without modification, are permitted provided
006 * that the following conditions are met:
007 *
008 * 1. Redistributions of source code must retain copyright
009 * statements and notices. Redistributions must also contain a
010 * copy of this document.
011 *
012 * 2. Redistributions in binary form must reproduce the
013 * above copyright notice, this list of conditions and the
014 * following disclaimer in the documentation and/or other
015 * materials provided with the distribution.
016 *
017 * 3. The name "JDBM" must not be used to endorse or promote
018 * products derived from this Software without prior written
019 * permission of Cees de Groot. For written permission,
020 * please contact cg@cdegroot.com.
021 *
022 * 4. Products derived from this Software may not be called "JDBM"
023 * nor may "JDBM" appear in their names without prior written
024 * permission of Cees de Groot.
025 *
026 * 5. Due credit should be given to the JDBM Project
027 * (http://jdbm.sourceforge.net/).
028 *
029 * THIS SOFTWARE IS PROVIDED BY THE JDBM PROJECT AND CONTRIBUTORS
030 * ``AS IS'' AND ANY EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT
031 * NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
032 * FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
033 * CEES DE GROOT OR ANY CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
034 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
035 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
036 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
037 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
038 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
039 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
040 * OF THE POSSIBILITY OF SUCH DAMAGE.
041 *
042 * Copyright 2001 (C) Alex Boisvert. All Rights Reserved.
043 * Contributions are Copyright (C) 2001 by their associated contributors.
044 *
045 */
046
047 package jdbm.helper;
048
049 import java.util.Comparator;
050 import java.io.Serializable;
051
052 import org.apache.directory.server.i18n.I18n;
053
054 /**
055 * Comparator for byte arrays.
056 *
057 * @author <a href="mailto:boisvert@intalio.com">Alex Boisvert</a>
058 * @version $Id: ByteArrayComparator.java,v 1.4 2002/05/31 06:33:20 boisvert Exp $
059 */
060 public final class ByteArrayComparator
061 implements Comparator, Serializable
062 {
063
064 /**
065 * Version id for serialization.
066 */
067 final static long serialVersionUID = 1L;
068
069
070 /**
071 * Compare two objects.
072 *
073 * @param obj1 First object
074 * @param obj2 Second object
075 * @return a positive integer if obj1 > obj2, 0 if obj1 == obj2,
076 * and a negative integer if obj1 < obj2
077 */
078 public int compare( Object obj1, Object obj2 )
079 {
080 if ( obj1 == null ) {
081 throw new IllegalArgumentException( I18n.err( I18n.ERR_525 ) );
082 }
083
084 if ( obj2 == null ) {
085 throw new IllegalArgumentException( I18n.err( I18n.ERR_526 ) );
086 }
087
088 return compareByteArray( (byte[]) obj1, (byte[]) obj2 );
089 }
090
091
092 /**
093 * Compare two byte arrays.
094 */
095 public static int compareByteArray( byte[] thisKey, byte[] otherKey )
096 {
097 int len = Math.min( thisKey.length, otherKey.length );
098
099 // compare the byte arrays
100 for ( int i=0; i<len; i++ ) {
101 if ( thisKey[i] >= 0 ) {
102 if ( otherKey[i] >= 0 ) {
103 // both positive
104 if ( thisKey[i] < otherKey[i] ) {
105 return -1;
106 } else if ( thisKey[i] > otherKey[i] ) {
107 return 1;
108 }
109 } else {
110 // otherKey is negative => greater (because MSB is 1)
111 return -1;
112 }
113 } else {
114 if ( otherKey[i] >= 0 ) {
115 // thisKey is negative => greater (because MSB is 1)
116 return 1;
117 } else {
118 // both negative
119 if ( thisKey[i] < otherKey[i] ) {
120 return -1;
121 } else if ( thisKey[i] > otherKey[i] ) {
122 return 1;
123 }
124 }
125 }
126 }
127 if ( thisKey.length == otherKey.length) {
128 return 0;
129 }
130 if ( thisKey.length < otherKey.length ) {
131 return -1;
132 }
133 return 1;
134 }
135
136 }